графика в С++

//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
 class domino
 {int a,x,y;
    public:
   domino(){}
  void vvod(void);
  void vivod(void);
  };
  void domino::vvod(void)
 { a=0;
  a=StrToInt(Edit1->Text);
  }
  void domino::vivod(void)
 {    x=Image1->Width/2,y=Image1->Height/2;
if (a=1){
  Image1->Canvas->Brush->Color=clRed;
Image1->Canvas->Pen->Color=clBlue;
Image1->Canvas->Pen->Width=3;
    Image1->Canvas->Rectangle(x+30,y+30,x-30,y-30);
}
else if (a=2){
Image1->Canvas->Brush->Color=clRed;
Image1->Canvas->Pen->Color=clBlue;
Image1->Canvas->Pen->Width=3;
    Image1->Canvas->Rectangle(x+20,y+20,x-20,y-20);
}
else if (a=3){
Image1->Canvas->Brush->Color=clRed;
Image1->Canvas->Pen->Color=clBlue;
Image1->Canvas->Pen->Width=3;
    Image1->Canvas->Rectangle(x+10,y+10,x-10,y-10);
}
  }
   domino D;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
 
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::Button1Click(TObject *Sender)
{D.vvod();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{exit(1);
 
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button3Click(TObject *Sender)
{D.vivod();
 
}
//---------------------------------------------------------------------------